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1 <HTML
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2 ><HEAD
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3 ><TITLE
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4 >SDL_JoystickGetBall</TITLE
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5 ><META
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6 NAME="GENERATOR"
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.61
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8 "><LINK
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9 REL="HOME"
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10 TITLE="SDL Library Documentation"
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11 HREF="index.html"><LINK
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12 REL="UP"
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13 TITLE="Joystick"
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14 HREF="joystick.html"><LINK
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15 REL="PREVIOUS"
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16 TITLE="SDL_JoystickGetButton"
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17 HREF="sdljoystickgetbutton.html"><LINK
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18 REL="NEXT"
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19 TITLE="SDL_JoystickClose"
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20 HREF="sdljoystickclose.html"></HEAD
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21 ><BODY
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22 CLASS="REFENTRY"
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23 BGCOLOR="#FFF8DC"
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24 TEXT="#000000"
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25 LINK="#0000ee"
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26 VLINK="#551a8b"
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27 ALINK="#ff0000"
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28 ><DIV
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29 CLASS="NAVHEADER"
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30 ><TABLE
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31 WIDTH="100%"
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32 BORDER="0"
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33 CELLPADDING="0"
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34 CELLSPACING="0"
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35 ><TR
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36 ><TH
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37 COLSPAN="3"
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38 ALIGN="center"
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39 >SDL Library Documentation</TH
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40 ></TR
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41 ><TR
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42 ><TD
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43 WIDTH="10%"
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44 ALIGN="left"
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45 VALIGN="bottom"
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46 ><A
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47 HREF="sdljoystickgetbutton.html"
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48 >Prev</A
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49 ></TD
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50 ><TD
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51 WIDTH="80%"
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52 ALIGN="center"
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53 VALIGN="bottom"
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54 ></TD
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55 ><TD
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56 WIDTH="10%"
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57 ALIGN="right"
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58 VALIGN="bottom"
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59 ><A
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60 HREF="sdljoystickclose.html"
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61 >Next</A
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62 ></TD
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63 ></TR
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64 ></TABLE
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65 ><HR
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66 ALIGN="LEFT"
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67 WIDTH="100%"></DIV
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68 ><H1
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69 ><A
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70 NAME="SDLJOYSTICKGETBALL"
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71 >SDL_JoystickGetBall</A
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72 ></H1
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73 ><DIV
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74 CLASS="REFNAMEDIV"
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75 ><A
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76 NAME="AEN5811"
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77 ></A
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78 ><H2
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79 >Name</H2
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80 >SDL_JoystickGetBall -- Get relative trackball motion</DIV
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81 ><DIV
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82 CLASS="REFSYNOPSISDIV"
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83 ><A
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84 NAME="AEN5814"
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85 ></A
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86 ><H2
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87 >Synopsis</H2
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88 ><DIV
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89 CLASS="FUNCSYNOPSIS"
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90 ><A
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91 NAME="AEN5815"
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92 ></A
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93 ><P
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94 ></P
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95 ><PRE
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96 CLASS="FUNCSYNOPSISINFO"
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97 >#include "SDL.h"</PRE
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98 ><P
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99 ><CODE
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100 ><CODE
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101 CLASS="FUNCDEF"
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102 >int <B
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103 CLASS="FSFUNC"
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104 >SDL_JoystickGetBall</B
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105 ></CODE
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106 >(SDL_Joystick *joystick, int ball, int *dx, int *dy);</CODE
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107 ></P
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108 ><P
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109 ></P
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110 ></DIV
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111 ></DIV
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112 ><DIV
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113 CLASS="REFSECT1"
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114 ><A
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115 NAME="AEN5821"
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116 ></A
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117 ><H2
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118 >Description</H2
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119 ><P
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120 >Get the <TT
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121 CLASS="PARAMETER"
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122 ><I
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123 >ball</I
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124 ></TT
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125 > axis change.</P
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126 ><P
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127 >Trackballs can only return relative motion since the last call to <TT
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128 CLASS="FUNCTION"
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129 >SDL_JoystickGetBall</TT
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130 >, these motion deltas a placed into <TT
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131 CLASS="PARAMETER"
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132 ><I
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133 >dx</I
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134 ></TT
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135 > and <TT
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136 CLASS="PARAMETER"
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137 ><I
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138 >dy</I
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139 ></TT
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140 >.</P
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141 ></DIV
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142 ><DIV
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143 CLASS="REFSECT1"
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144 ><A
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145 NAME="AEN5829"
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146 ></A
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147 ><H2
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148 >Return Value</H2
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149 ><P
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150 >Returns <SPAN
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151 CLASS="RETURNVALUE"
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152 >0</SPAN
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153 > on success or <SPAN
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154 CLASS="RETURNVALUE"
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155 >-1</SPAN
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156 > on failure</P
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157 ></DIV
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158 ><DIV
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159 CLASS="REFSECT1"
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160 ><A
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161 NAME="AEN5834"
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162 ></A
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163 ><H2
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164 >Examples</H2
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165 ><P
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166 ><PRE
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167 CLASS="PROGRAMLISTING"
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168 >int delta_x, delta_y;
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169 SDL_Joystick *joy;
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170 .
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171 .
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172 .
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173 SDL_JoystickUpdate();
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174 if(SDL_JoystickGetBall(joy, 0, &delta_x, &delta_y)==-1)
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175 printf("TrackBall Read Error!\n");
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176 printf("Trackball Delta- X:%d, Y:%d\n", delta_x, delta_y);</PRE
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177 ></P
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178 ></DIV
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179 ><DIV
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180 CLASS="REFSECT1"
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181 ><A
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182 NAME="AEN5838"
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183 ></A
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184 ><H2
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185 >See Also</H2
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186 ><P
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187 ><A
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188 HREF="sdljoysticknumballs.html"
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189 ><TT
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190 CLASS="FUNCTION"
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191 >SDL_JoystickNumBalls</TT
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192 ></A
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193 ></P
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194 ></DIV
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195 ><DIV
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196 CLASS="NAVFOOTER"
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197 ><HR
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198 ALIGN="LEFT"
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199 WIDTH="100%"><TABLE
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200 WIDTH="100%"
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201 BORDER="0"
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202 CELLPADDING="0"
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203 CELLSPACING="0"
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204 ><TR
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205 ><TD
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206 WIDTH="33%"
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207 ALIGN="left"
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208 VALIGN="top"
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209 ><A
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210 HREF="sdljoystickgetbutton.html"
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211 >Prev</A
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212 ></TD
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213 ><TD
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214 WIDTH="34%"
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215 ALIGN="center"
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216 VALIGN="top"
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217 ><A
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218 HREF="index.html"
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219 >Home</A
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220 ></TD
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221 ><TD
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222 WIDTH="33%"
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223 ALIGN="right"
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224 VALIGN="top"
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225 ><A
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226 HREF="sdljoystickclose.html"
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227 >Next</A
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228 ></TD
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229 ></TR
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230 ><TR
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231 ><TD
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232 WIDTH="33%"
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233 ALIGN="left"
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234 VALIGN="top"
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235 >SDL_JoystickGetButton</TD
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236 ><TD
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237 WIDTH="34%"
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238 ALIGN="center"
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239 VALIGN="top"
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240 ><A
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241 HREF="joystick.html"
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242 >Up</A
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243 ></TD
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244 ><TD
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245 WIDTH="33%"
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246 ALIGN="right"
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247 VALIGN="top"
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248 >SDL_JoystickClose</TD
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249 ></TR
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250 ></TABLE
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251 ></DIV
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252 ></BODY
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253 ></HTML
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254 > |
